/*
 * @Date: 2023-11-7 15:15:32
 * @LastEditors: 老友  1527308832@qq.com
 * @LastEditTime: 2023-11-7 11:13:17
 * @FilePath: \cesium-tyro-blog\src\utils\Material\EllipsoidFadeMaterialProperty.js
 * @Description: 扩散圆材质
 */
import * as Cesium from 'cesium'
 
export default class EllipsoidFadeMaterialProperty {
  constructor(options) {
    this._definitionChanged = new Cesium.Event();
    this._color = undefined;
    this._colorSubscription = undefined;
    this._time = (new Date()).getTime();
    this.color = options.color;
    this.duration = options.duration;
  };
 
  get isConstant() {
    return false;
  }
 
  get definitionChanged() {
    return this._definitionChanged;
  }
 
  getType(time) {
    return Cesium.Material.EllipsoidFadeMaterialType;
  }
 
  getValue(time, result) {
    if (!Cesium.defined(result)) {
      result = {};
    }
 
    result.color = Cesium.Property.getValueOrClonedDefault(this._color, time, Cesium.Color.WHITE, result.color);
    result.time = (((new Date()).getTime() - this._time) % this.duration) / this.duration;
    return result;
  }
 
  equals(other) {
    return (this === other ||
      (other instanceof EllipsoidFadeMaterialProperty &&
        Property.equals(this._color, other._color))
    )
  }
}
 
Object.defineProperties(EllipsoidFadeMaterialProperty.prototype, {
  color: Cesium.createPropertyDescriptor('color'),
})
 
// Cesium.EllipsoidFadeMaterialProperty = EllipsoidFadeMaterialProperty;
Cesium.Material.EllipsoidFadeMaterialProperty = 'EllipsoidFadeMaterialProperty';
Cesium.Material.EllipsoidFadeMaterialType = 'EllipsoidFadeMaterialType';
Cesium.Material.EllipsoidFadeMaterialSource =
  `
  czm_material czm_getMaterial(czm_materialInput materialInput)
  {
    czm_material material = czm_getDefaultMaterial(materialInput);
    material.diffuse = 1.5 * color.rgb;
    vec2 st = materialInput.st;
    float dis = distance(st, vec2(0.5, 0.5));
    float per = fract(time);
    if(dis > per * 0.5){
      material.alpha = 0.0;
      discard;
    }else {
      material.alpha = color.a  * dis / per / 1.0;
    }
    return material;
  }
  `
 
Cesium.Material._materialCache.addMaterial(Cesium.Material.EllipsoidFadeMaterialType, {
  fabric: {
    type: Cesium.Material.EllipsoidFadeMaterialType,
    uniforms: {
      color: new Cesium.Color(1.0, 0.0, 0.0, 1.0),
      time: 1 ,
     
    },
    source: Cesium.Material.EllipsoidFadeMaterialSource
  },
  translucent: function (material) {
    return true;
  }
})
console.log('成功加载扩散圆材质');
 
 
// ? 如何使用
// import EllipsoidFadeMaterialProperty from '@/utils/Material/EllipsoidFadeMaterialProperty.js'
 
// material: new EllipsoidFadeMaterialProperty({
//   color: new Cesium.Color(1.0, 1.0, 0.0, 0.8),
//   duration: 3000,
// })